Driven by a desire to use polysaccharides in various applications, researchers have explored for polysaccharides that are biodegradable and that can be made economically from renewably sourced feedstocks. One such polysaccharide is alpha-1,3-glucan, an insoluble glucan polymer characterized by having alpha-1,3-glycosidic linkages. This polymer has been prepared, for example, using a glucosyltransferase enzyme isolated from Streptococcus salivarius (Simpson et al., Microbiology 141:1451-1460, 1995). Also for example, U.S. Pat. No. 7,000,000 disclosed the preparation of a spun fiber from enzymatically produced poly alpha-1,3-glucan.
Enzymatic synthesis of various glucan polymers has been performed in reactions in which polysaccharides (e.g., dextran) or oligosaccharides (e.g., from hydrolyzed polysaccharide) have been added to affect glucosyltransferase function (e.g., Koga et al., 1983, J. Gen. Microbiol. 129:751-754; Komatsu et al., 2011, FEBS J. 278:531-540; Simpson et al.; O'Brien et al., U.S. Pat. No. 8,642,757). Despite these disclosures, there is little understanding with regard to modulating glucosyltransferase reactions for insoluble alpha-1,3-glucan synthesis.